Heat transferring means



Au@ 11, 1931. N.'/P.SETCHK1N 1,"8135762 HEAT TRANSFERRING MEANS Original Filed June 23, 1926 SYSheefLs-Sheen l gvvuantoz N. F. SETCH K\ N Aug; 1l. 1931.4

N. P. sl-:Tcvl-IKINr HEAT' TRANSFERRING MEANS 2 z O .t .rv u Q im m S t. q@ e1 e h d s l l 5 l 6 T H E l M 311 I e m n' J d T M 4 4 M l I T F w l a R .m m 1b Z r o NJB. SETCHKI N- @13 his @Mor/mm3 P. sTcHKlN HEAT TRANSFERRI NG MEANS' ginal 'Filed June 23, 1925' 5 Sheets-Sheet 4 57 .4. OUTLET Ori GAS /vLaT Patented Aug. l1, 1931 UNITED STAT ES PATENT or-"rics lfCl-ILASy P. SE'TCHKIN, OF'NW YORK, N. Y.,` ASSIGNOR TO DOHERTY RESEARCI CMANY, F YORK, N. Y., A "CORPORATION OF DEiAVVARE HEAT mnsusrnnaine Meeus Application slee .rune 23, 1926, serial No. 117,942. nene'wea october 5, 192s.

This invention relates to improvements in heat transferring apparatus and more particularly to high pressure recuperators in which heat may be imparted to air flowing there= 1B through, the medium for supplying heat to the air under high pressure being hot gases under low pressure flowing through the recuperator. In general, the objects of the invention are l to provide a recuperator in which the gas flue shall consists of anuniber of passages or passes arranged in compact relation in a cuboidal or elongated body; to so construct the recuperator body as to adapt it to withn stand high internal pressure; to construct the recuperator body in such c manner that the ends thereof 'may consistof removable covers on the inside face of which are passages which .v cooperate with the longitudinally extending passages in the main portion of the body' to form a continuous flue; to provide inthe va-Y rious passages constituting the nue a heattransferring means which `shall provide a long devious path in which the air can be heated and which shall insure an intimate transfer Contact between the air and the hot gases flowing through the passages; to provide a method of'constructing the heat-transrenin-g means; to supoprt the heat-transfer;

W0 ring means in a manner which will permit of free expansion and contraction thereof; to provide for suitable control of the hot gases by means of which the air is to be heated; and to provide other features of construction as will more fully appear hereinafter.

Referring to the drawings in 'which the preferred recuperator construction is shown, Fig. 1 is a view showing schematically the manner of controlling the flow of hot exhaust gases from an engine through arecuperatgr, the `latter being diagrammatical'ly represent# ed for simplicity of showing:

Fig. 2 is in general a top plan view of the '45 preferred r-ecuperator constructiom parts be ing broken away to show the manner of ar,

ranging or groupingv the various 'passages which together constitute a continuous gas Hue;

Fig. -3 is a. vertical cross=section of the re:-

cuperator taken'on line 23e-'3 of F ig. 2' to show the interior construction;

F ig. 4 is a vertical section of the recuperator shown in Figs. 2 and 3, thev view being taken on a plane passing through lines 4-4 of Figs. 2 and 3;

Fig. 5 illustrates the first form into which the tubes comprising the` heat-transferring means are bent in theprocess of manufacture;

Fig. 6 is an end elevation of Fig. 5;

Fig. 7 illustrates in perspective the second form into which the tubes. are bent in the The manner of forming the tubesv which make 'up the heat-transferring means of the recuperator will firstv bev described,- reference being made more particularly to Figs. 5 t0 l1 for this purpose.y f

The tubing from which an individual resupera/cor coil is to be formed is -rst bent into the general form shown in side elevation and end elevation in Figures 5 and 6 respectively. The tubing may be of Alborized cold` drawn seamless steel tubing or other 'suitable metal or alloyed metal tubing. Y

The figures show only such a portion of a completev coil as suilices to illustrate the success'ive steps followed in shaping the coil. In practice the coils may consist of any convenlent number of loops. As shown in Figure 5, the form imparted to the tubing in the first step consists of a series of loops t1, t2, s1, s2, t3, s3 s4, between which are the substantially straight portions a, o, c, d, c. f, and g. In the form shown in Figure l5 the. adjacent loops such as t1 and 81, t2 and s2, are shown in abutting relation, but it is not abso- .l'utelynecessary that the loops be shaped in exactly such a relation. The bends could ybe made in such a manner that the substantially straight portions would be parallel to each other, but inasmuch as the straight portions must be eventually bent at an angle to each other, it is preferred to impart the angular relation between the bends in the first step. It is to be especially noted that at the end of the first step, as shown in Figures 5 and 6, the axis through the center of the tubing of all of the loops and all of the substantially straight portions lies in a single plane TT. In the second step of the forming process the coil is bent into the shape shown in perspective in Figure 7 and shown in actual end elevation in Figure S. The coil as shown in Figures 5 and 6 may be conveniently shaped into the form shown in Figures 7 and 8 by some such means as is presently described. Referring to Figure 5, and especially to the axis therethrough, the loops t1, t2, t3 and t4 are clamped so as to be held firmly in the plane T-T, as indicated in Figure 6. The loops s1, s2 and 8'* are then forced laterally to the left as viewed in Figure 6, so that the loops just mentioned will lie in a plane S-S which is parallel to the plane T-T.

Specifically, at the end of the second step, as is illustrated in Figures 7 and 8, and referring especially to the axis therethrough, the loop t1, the substantially straight portion a, and the loop t2, all lie in the plane T-Tg the straight portion b lies at an angle between the two planes joining the loop t2 in plane T-T with the loop s1 in plane S-Sg the loop S1, the straight portion 0 and the loop s2 lie in the plane S-S; the straight portion d lies at an angle between the two planes joining the loop s2 in plane S-S with the loop t3 in the plane T T; the loop t3, the straight portion e and the loop t4 lie in the .plane T--T;. the straight portion f lies at an angle between the two planes joining the loop t4 in plane T-T with the loop s3 in plane S-S; the loop 83 and straight portion g and the loop s4 lie in a plane S-S. More concisely the loops are distributed in the two planes while the substantially straight portions lie, some in one plane, others in the other plane, and still others atan angle between tlie two planes.

In the third and final step of forming the tube the coil is bent into the shape shown in side elevation in Figure 9 and in end elevation in Figure l0. Referring to Figure 8. The final bending is accomplished by forcing the loops in the plane T-T towards each other simultaneously with forcing the loops in plane S-S toward each other. However, the loops are preferably not forced into abutting relation for reasons which will presently appear. At the end of the third step the loops and the substantially straight portions are in a very compact relation so that the assage through the tubing affords a long devious path. This is exactly the condition which is desired. u i

Figure 11 illustrates a section taken on the line 11.-11 of Figure 9. This ligure clearly shows both the location of the loops intwo parallel planes and also the locationnof the intervening straight portions, s ome oi which lie in one plane, others of which lie in the other plane and still others which lie at an angle between the two planes.

While the foregoing description sets forth in detail the preferred mehod of shaping the coil and the preferred relative positions of the loops and the intervening straight portions it will be evident to those skilled in the art that some departure may be made therefrom without departing from the spirit of the invention. Thus coils of various specific forms may be made which have loops distributed in two parallel planes and having intervening straight portions in and atan angle to these two planes.

It will be observed that the form of the tube assumed after the second step is the same as that assumed after the third step as regards the location of the loops and the bends therebetween in relation to two parallel planes. The primary difference between the two forms is that in the latter there is a greater number of bends in a given space than there is in the former and consequently that a longer flow path is provided in the more compact form.

As between the tube forms resulting from the second and third steps above described, the more compact form is preferred to be used in the recuperator primarily on account of the larger flow path but it is within the scope of the invention to employ either form or combinations of the two. Either form obviously provides a single heat-transferring sinuous conduit embodying in its integral structure a plurality of pairs of successive hair pin type bends lying alternately in one of two closely spaced parallel planes, with the result that the maximum amount of heat will be extracted from the hot gases which figw thcreover and moreover either form will cause the hot gases to flow in a more or less devious path among the bends.

Referring now more particularly to Figs.A 2, 3 and l for a disclosure of other constructional features of the improved recuperator, reference characters 10, 11 and 12 indicate, respectively, a cylindrical shell and the end closures which form a part thereof. The end closures are secured to the cylindrical shell 10 in any suitable manner as by suitable securing means 13 passed through flanges 14 extending radially from the shell and end closures. lVithin the shell is contained a body of refractory material, that part of the body within the cylindrical shell 10 being for convenience of description indicated by reference character 15, that within the end closure 11 by 16, and that within the closure 12 by 17. A tight joint is maintained in any suitable manner between the opposed faces asienta of the refractory body sections but preferably by means of sealing rings 18 of asbestos disposed in grooves in the opposing surfaces. The joint between the lower end of the re` fractory body 15 and the body 16 in the bottom cap or closure member preferably ine cludes a ring plate 19 which at its outer edge is secured between the securing iianges 13. This ring 'plate serves to reinforce the constr'uo ion and also serves to maintain the body 15 in place when the bottom cap 11 is removed. At the lower end of the recuperator the two bodies 15 and 16 meet substantially in the plane of the joint between the shell 10 and end cap 11 whereas at the upper end of the recuperator the bodies preferably meet above the capand shell joint in order to simplify other features of construction as will pres ently appear.

The main or central refractory body 15 is provided with a plurality of parallelly disposed flue passages G, H, I, J, K and L which are connected in series in the order named and in these iue passages are located banks of tubes A, B, C, D, E and F, these banks being connected in series in the order named.

The hot gases enter the recuperator by way of a conduit in and flow downwardly in the flue passage G, thence across to the flue passage H by way of a passage GH (Figs. 3 andv 4i.) at the foot of a diametral partition wall DP, thence upwardly inthe passage H and across to the adjacent iiue passage I by way of a connecting passage HI (Figs. 2 and 3.) extending therebetween at the top thereof, thence downwardly in the flue passage I and across to the flue passage J by way of a connecting passage IJ (Fig. u 4) extending through the partition wall DP at the foot thereof, thence upwardly in the flue passage J and across to the flue passage K by way of connecting vassage JK (F igs; 2 andv 4) extending di of, thence downwardly in the passage K and into the passage L by way of a connecting passage KL (Fig. 4,) in the foot of the partition wall DP and thence upwardly in the flue passage L and out through the conduit n.

Each tube bank ifs shown as comprising a plurality of individual tubes of the form previously described. The individual tubes, for convenience, may be identified by reference charaoter 20, the ends Vof theA tubes being connected to upper and lower headers or manifolds 22 and 24, respectively, in any suitable inanneri each: other through the oassageways GH, IJ and KL at the bottone of the dialnctral parti-- tion wall DP are connected' by conduits 26 which eXtendi through said! passageways. Those tubebanks, which are connected' at their tops, that is to say, the tube banks B, C and D, E may have their headers formed as a single piece, theii-ntermediate `portion for 'conerebetween at the top there- Those headers 24 which facev venienoe of description being indicated at 28.

In the present case each tube bank is shown as made up of four individual tubes 2O of the type previously described but the invention is not limited to any particular number of tubes in a bank, The number of tubes employed will depend primarily on the volume of air to be heated and/or on the amount of heat contained in the hot gases. While it is pref# ferred to have the heat-transferring surfaces made from tubes of the form indicated it 'may be stated that as regards certain other features of the inventionthe due passage 'ar-v rangement for example-#the invention is not limited to this particular type of tube formation.

The in divi dual tubes 20 while they7 are connected at their opposite ends to headersare not supported by these headers. The preferred manner of supporting the tube bank 1s to support the lowermost bends of the tubes on ledges Ofand 31 projecting from the opposed side walls of the due passage near the bottoni of the respective passages (see Fig. 3). The ledges 31 are formed as a step on diametral partition DP above the opening extending through the foot ofthe partition, the ledges 30 also being in thenature of a step in the opposite wall as will be readily understood by reference to Figi 3. The bottom headers 24 are held suspended in space with-Y out touching oribeing supported by any por'- tion of the refractory body constituting the interior of shell.

In order to maintain the various bends o tube iny a definite spaced relation with respect to eachl other spacers 32 are inserted between adjacent bends ofthe tube coils. These spacers are preferably made of asbestos whereby to insulate the adjacent loops from each othe'r and whereby to provide a somewhat yielding or cushioned support between the loops. These vspacers are preferably of a lengthto extend transversely across the tube bank, the disposition of the adjacent loops being such the, spacer strips may be passed through one set of loops and between adjacent loops alternately. In order to avoid undue crowding of the disclosure only a few of the spacers have been shown in place.

As previously explained, the various passages which make up the gas flue are con` nested in series to` form a continuous gas due. Referring to Fig. 3 it will be noted that the passages extend the length of the refractory body 15'. The connect-ing of the 'passages in seriesfis effectedv by passages formed either wholly or'partly within the refractorybodes 16 and 17 in the end closures or cpove'rs'll and 12 respectively. In lthe case of the bottom closure the connectingpassages are formed partly in the main refractory body 15 at ,the

foot of the diametralpartition 131j and partly in the body 16 whereas in the'upper closure body I7 the connecting passages are formed iso Wholly therein. It will be observed that by virtue of making the recuperator in three sections as indicated, that is tosay, of a main central body and end closures, the entire assembly is materially siniplied and access may readily be had to the interior of-the recuperator by the simple act of removing one or the other or both of the end closures.

The upper headers 22 of the tube banks F and A are connected to air inlet and outlet conduit-s 33 and 34 respectively, the conduits passing through stuffing boxes 35 which permit relative longitudinal movement of the conduits as the tube banks expand or contract as the case may be under variations in temperature.

It need hardly be pointed out that the air to be heated will be passed through the tubes of the tube banks in opposition to the flow of the hot gases over and through said banks. Suitable controlling valves 33a and 34a will be provided in air inlet and outlet conduits and 34 respectively.

The gases to be utilized in heating the air passing through the tube banks are preferably derived, in accordance with the present invention, from an internal-combustion engine of a type adapted to use-the air which has been preheated.

he-n hot gases from an internal combustion engine are to be passed through the recuperator, the connections shown in Fig. l arepreferred. In this view the engine is diagrammatically represented at 50. Be'- tween the engine and the inlet m of the recuperator which is also diagrammatically represented in Fig. l, there is provided a conduit 51 through Which the engine exhaust gases pass to the recuperator. The discharge end of the conduit 51 isshown as received Within a casing 52 having a petticoat-type nozzle 53 therein into which a flaring nozzle 54 at the end of the conduit 51 projects, the

casing making connection with the recuperator inlet by means of a suitable conduit 55. Connecting With the casing 52 in front of the nozzler53 is a conduit Which is provided With a valve 57 shown as of the gate type. Conduit 56 is connected With a preheater not shown for introducing hot gases into the recuperator for a purpose that will presently appear.

Extending as a branch from the conduit is a vent conduit 58 containing a safety1 valve 59 of any approved type therein for relieving the pressure Within the recuperator should there be an explosion Within the recuperator from one cause or another or in case the gas pressure exceeds a predetermined value. Extending from the outlet a of the recuperator is an exhaust conduit 60 which connects with the conduit 58 at a point above'the safety valve 59. This conduit is preferably provided with a valve 61 for controlling the flow of the gases from the recuperator.

The mode of operation of the gas controlling system above described is as follows:

lVhen it is desired that the recuperative internal combustion engine be started after it has been standing some time and Vis cold, the gate valve 57 is opened and hot gases from the preheater are passed through the conduit 56, through the nozzle 53 into the gas inlet m of the recuperator. The passage of these hot gases from the preheater through the recuperator supplies the compressed-air Within the recuperator coils With sufficient heat so that the engine may be started. Then the engine is started, and during the periodv in Which the engine is being warmed up, the gate-valve 57 is left open as shown. Hot exhaust gases from the engine pass through the conduit 5l through the nozzles 54, 53 and enter the recuperator through the hot gas inlet m. During the lWarming-up period in which the gate-valve 57 is left open, hot gases from the preheater supplement the hot gases from the engine thereby making sure that compressed air is supplied With suiiicient heat to maintain the temperature of the compressed-air leaving the recuperator at the proper level. The nozzles 53. 54; are so designed that theI passage of the exhaust gases from engine through the nozzles produces a slight suction and tends to draw the hot gases from the preheater into the main gas stream.

At the end of the Warming-up period the exhaust gases from the engine are able to supply the compressed-air with a suflicient amount of heat. Consequently, at this time the gate-valve 57 is closed and the supply of additional hot gases from the preheater is discontinued.

In the event that the pressure of the gases entering the recuperator should rise to an abnormal value, the safety valve 59 Will open and discharge the gases directly into the vent conduit 58.

lVhat I claim is l. In combination, a body having a group of passages arranged side by side anda second similarly arranged group disposed beside the lirst group, a partition separating the tivo groups, the passages being connected in series whereby gases may flow through the passages in succession, and interconnected heat-transferring surfaces arranged in each of said passages.

2. ln combination, a body having a group of longitudinally extending passages therein, the passages being connected in series to form a continuous flue for the iovv of gases, a bank of tubes in each of said passages, the banks being connected in series to form a continuous path for the flow of fluid therethrough, the tubes being connected to manifolds, and means independent of the maniranged in two parallel planes, the loops in one plane so arranged with respect to the loops in the other plane that the adjacent surfaces of the loops in one plane are opposite the opening formed by the adjacent loop in the other plane and heat-insulating means of' yielding material disposed between the adj acent loops in the same plane and extending through the adjacent loops in the other plane.

4. In combination, a closed body having a group of longitudinally extending passages therein, the ends of the body having removable covers the interiors of which co-operate with the passages to form a continuous flue, a bank of tubes arranged in each passage, the banks being connected in series to form a continuous path for the fiow of fluid therethrough, manifolds to which the tube ends are connected and which extend into the passages in the covers, and means for supporting the weight of the tube banks independently of the covers.

5. In a heat-interchanging apparatus, the combination of a body having a passage therein, a second passage adjacent to and parallel therewith, said passages being in communication at their lower ends, a third passage alongside the second passage and in communication therewith at their upper ends, a fourth passage arranged alongside the first passage and in communication with the third passage at their lower ends, a fifth passage arranged alongside the fourth passage and in communication therewith at their upper ends, a sixth passage arranged alongside the third passage and in communication with the fifth passage `at their lower ends, said passages constituting a continuous flue for the flow of hot gases, and heat-transferring means located in said passages.

6. A zig-zag coil comprising a series of hair-pin-type bends whereof every other pair of successive loops lie in a plane in spaced parallel relation to the plane in which the other pairs of loops lie.

7. A Zig-zag coil comprising aseries of hair-pin-type bends whereof every other pair of successive loops lie in a plane in spaced parallel relation to the plane in which of which lie in one plane, the next two loops in a plane parallel to the first, the next two loops in the same plane as the first two loops of the series, the leg between the second andk third loops extending diagonally between said planes, and the leg between the fourth and fifth loops likewise extending diagonally between said planes but transversely of the first-mentioned leg.

10. In combination a-closed body having a group of longitudinally extending passages forming a continuous flue therein, removable covers on the ends of said body, a bank of tubes arranged in each of said passages, the banks being connected in series to form a continuous path for the flow of iiuid therethrough, and manifolds to which the ends of said tubes are connected.

11. In a heat interchanging apparatus, a cylindrical casing forming a shell surrounding a body of refractory material having a plurality of passages extending longitudinally therethrough, means connecting said passages in the series to form a continuous flue, tubes arranged in each of said passages and interconnected to Vform a continuous path for the flow of fluid therethrough, and covers closing the ends of said cylinder.

f 12. In a heat interchanging apparatus, a body of refractory material having a plurality yof passages extending therethrough, means connecting said passages in series, and tubes arranged in` each of the said passages and interconnected to form a continuous path for the flow of fluid therethrough.

In. testimony whereof I affix my signature.

NICHOLAS vP. SETCHKIN.

the other pairs of loops lie, the adjacent loops y in the individual planes being in close proximity to each other.

8. A tube bent upon itself into a series of bends of the hair-pin-type, the first two loops of which lie in one plane, the next two loops in a plane parallel to the first, and the next two loops in the same plane as the first two loops of the series.

9. A tube bent upon itself into a series of bends of the hair-pin-type, the first two loops 

